1. Field of the Invention
This invention relates to a microfilm reader for simultaneous processing of several microfilms.
2. Description of the Prior Art
Microfilm readers having more than one micropicture stacked in parallel planes between a light source and a projection objective are known. Such an arrangement is shown in U.S. Pat. No. 3,319,518. In this disclosure is shown that the projection objective can be movably positioned in the direction of the projection axis. When reading the microfilm, located more remote from the objective than the first microfilm, the projected image generally has poor picture quality, since the further removed microfilm has to be projected through those films closer to the objective. The resulting loss in picture quality can be tolerated only when no more than two successive microfilms are involved. However, if more than two microfilms are stacked in the light beam, then the picture quality of those microfilms further positioned than two-fold the distance from the projection objective suffers to such a degree that it has been considered impractical to use a microfilm reader with more than two microfilms following each other. However, there is a need for a system wherein as large as possible a number of microfilms is combined into one operational unit for avoiding the time consuming exchange of microfiches.